Regulated gas flow control and pressure regulation devices are attached to portable medical gas or oxygen cylinders and used by those requiring medical gas delivery, most commonly, in response to a Doctor's prescription for oxygen. Such gas or oxygen delivery devices are used by individuals in all walks of life at work and during recreational times. The gas delivery devices are often times subject to fairly rough handling including tip-over events and severe impacts with solid objects during use, handling, transport and storage. The response from the medical gas regulator industry has been to produce gas regulator and flow control devices that are fairly sturdy in construction. However, the devices still fail on occasion due to excessive force impacts that occur during use as well as during transport and refilling operations.
A practical consideration in the design of portable gas delivery devices is size and weight. Excessive size or weight makes the device less attractive to end consumers, since oxygen delivery devices are typically carried by hand or pulled along in a small “pull cart” or dolly. Thus, it is desired that improved impact protection should be accomplished without significant additional weight added to the devices.
Portable gas delivery devices of the prior art also utilize a mechanical interface commonly referred to as a “post valve” for connecting a pressure regulator device to the tank. The post valve is attached to a pressurized tank via a threaded interface, and a regulator device or combination regulator/flow control device is then attached to the post valve. One example of such a post valve is shown in U.S. Pat. No. 6,148,841 to Davidson. An example of a regulator that connects to the post valve of the '841 patent is shown in U.S. Pat. No. 6,082,396 to Davidson. Refilling tanks incorporating such devices includes the initial step of opening the flow control section of the regulator and drawing a 25 inches of mercury vacuum on the system at the flow control outlet port of the regulator. Atmospheric air may potentially be drawn in through the relief valve of the regulator, and such a result is undesirable. Relief valves in pressure regulators typically activate at 1.5 times the normal working pressure of the regulator, or at about 75 PSI. Further, the seals of the flow control portion and seals in the post valve interface of the prior art regulator present potential leak points during system evacuation steps prior to refilling the tank or cylinder. Thus a design that eliminates the post valve to regulator interface and other potential leak points is desired.
What is needed is a gas delivery device with an impact protection mechanism that is adaptable to a wide variety of existing gas regulation device designs and provides improved impact protection to prevent physical damage to the pressure regulator/flow control devices. Further, the system should include design aspects to reduce difficulties encountered during refilling procedures and eliminate potential leak problems associated with prior art designs. In addition, the impact protection device should enhance the functionality of the entire gas delivery system without adding substantial weight or cost thereto.